The technical field of this invention is treatment of urological defects and, in particular, the treatment of vesicoureteral reflux.
The discharge of urine via the urinary tract is essential to the maintenance of healthy kidney functions. In the normal individual, urine flows from the kidneys through the ureters into the bladder. From there it is periodically released via the urethra. The terminus of the ureter at the bladder normally provides a competent sphincter which insures that urine flows from the ureter to the bladder. However, if this junction is impaired, vesicoureteral reflux can occur wherein urine from the bladder can return to the kidney, particularly during voiding or when pressure is exerted upon the bladder.
Vesicoureteral reflux can cause renal damage or even renal failure either directly as a result of high pressures transmitted to the kidney or indirectly as a result of infections introduced by retromigration of bacteria into the kidneys. These problems can be particularly acute in newborns and infants when incompetent ureterovesical junctions are present. In some children, the risk of kidney damage can be reduced by antibiotic therapies and minor reflux problems will disappear over time with increased developmental maturity.
However, when vesicoureteral reflux is severe, surgery has often been necessary to repair the disfunctional junction. In most of these approaches, the ureter is dissected from the bladder and re-implanted to lengthen or otherwise restrict the submucosal tunnel. By reconfiguring the tunnel, closure of the ureteral lumen can be markedly improved as a result of intravesical pressure as the bladder fills.
Unfortunately, these open surgical procedures always carry risks, including collateral damage to other urological structures and the possible introduction of further infectious agents. These risks are particularly pronounced when surgery is required on newborns or infants.
The endoscopic treatment of reflux was first introduced in 1981 by Matouschek when he injected polytetrafluorethylene (Teflon) paste in the subureteral region of a patient. In this approach, a bolus of Teflon paste is introduced into the subureteral region to restrict or reshape the submucosal tunnel. In a manner similar to surgical procedures, the effective length of the submucosal tunnel is increased and effective closure, as the bladder fills, is likewise achieved. This technique was popularized by O'Donnell and Puri, and has now been utilized to treat vesicoureteral reflux in over 8000 children.
The use of Teflon paste in the pediatric population is not without controversy due to evidence of Teflon particle migration to the lungs and nodes and granuloma formation in both animal models and in humans. Nonetheless, there are definite advantages in treating these patients endoscopically. The method is simple and can be completed in less than 15 minutes, it has a success rate of over 85% with a low morbidity, and can be performed in an outpatient basis.
Various other substances have been proposed as safer alternate implant materials, including collagen, autologous fat and fibroblast injections, polyvinyl alcohol foam (Ivalon) and glass; however each has its disadvantages. Volume loss has been identified as a problem with collagen, autologous fat and fibroblast injections. Granuloma formation with possible latent carcinogenic effects has been associated with Ivalon and glass particles as well as Teflon paste.
There exists a need for better methods and systems for treatment of vesicoureteral reflux and related urological disorders. In particular, approaches that avoid open reconstructive surgery while providing effective control of urinary reflux would satisfy a long-felt need in the field, especially in the treatment of neonatal birth defects.